The SIG P320 Custom Works Fire Control Group(FCU) is the heart of the modular P320 platform. The P320 is perfectly suited to adapt to the users demands. The P320 can be configured with various slides, barrels, grip modules and magazines. The SIG Custom Works FCU features a Black PVD finished frame, Black PVD finished skeletonized trigger, custom FCU serial number. Compatible with all 9mm/357SIG,40SW P320 Post-Upgrade accessories.